Important Legal Note: HK Modular is often a commercial typeface created by professional foundries (such as Hanken Design Co.). However, there are "knockoffs," open-source variants, or specific promotional free versions available. For the purposes of this article focused on the "top" free downloads, we are looking for legal, high-quality alternatives or legitimate free releases.

Here are the top 3 places to find HK Modular Bold or its exact open-source equivalent:

Windows:

Mac:

Linux:

Web use (CSS):
If the license allows, upload the font to your server and use:

@font-face 
  font-family: 'HK Modular Bold';
  src: url('hk-modular-bold.woff2') format('woff2');
  font-weight: bold;

While the exact "HK Modular Bold" may not always be native to Google Fonts, Orbitron is geometrically identical in spirit. It is a free, open-source geometric sans-serif that offers a heavy bold weight. If you need a 100% legal download for commercial use, start here.

Many independent type designers release "HK-style" modular fonts for free (or "pay what you want") to build their portfolios. Search for "HK Modular Bold free download" on Behance. Often, a young designer will have created a clone that is 99% visually identical and legally free for personal use.

Warning: Avoid "free font" aggregators that offer cracked commercial software. Stick to the sources above to avoid malware and legal trouble.